The director-general of the World Trade Organization says negotiators have failed to craft the first global trade deal in more than a decade, which could have given the world economy a $1 trillion boost.

Roberto Azevedo says diplomats from the WTO's 159 members tried hard but "cannot cross the finish line here in Geneva" ahead of a summit where ministers were to have signed the deal in Bali, Indonesia, next week.

Azevedo told reporters Tuesday that without a deal the organization's credibility will suffer, because it will only be viewed as a trade court and no longer as a forum for governments to negotiate trade agreements.

He says negotiators in the past few days became deadlocked over the details.